1. Field of the Invention
The present invention relates to encryption key restoring methods, information processing apparatus, and encryption key restoring programs. More particularly, it relates to an encryption key restoring method, an information processing apparatus, and an encryption key restoring program whereby an encryption key used for encrypting data stored in an internal storage unit can be restored.
2. Description of the Related Art
In conventional information processing apparatus, it is often required to encrypt internally stored data and save it in a hard disk drive (HDD), an NVRAM, or the like. For example, Japanese Laid-Open Patent Application Nos. 2002-024091 and 2005-158043 disclose methods for protecting data saved in such a storage unit by encrypting the data. In information processing apparatus incorporating such methods, an encryption key used for data encryption is conventionally stored in a TPM (Trusted Platform Module) so as to prevent the encryption key from being compromised.
In an information processing apparatus in which an encryption key for data stored in the HDD, NVRAM, or the like is stored in a TPM, it is difficult to decrypt the data stored even if the HDD or NVRAM is stolen, for example, because the TPM in which the encryption key is stored is an integral part of a controller board.
However, in the above information processing apparatus, if the controller board were to be replaced due to a defective component or an end of life of a component, for example, the TPM with the stored encryption key in it would also be replaced. Thus, replacing the controller board leads to an inability to decrypt the data stored in the storage unit such as the HDD or NVRAM. Unless the data stored in the storage unit can be utilized, the conventional information processing apparatus cannot be even started up.
In practice, it is rare to replace only a defective component on the controller board in an information processing apparatus; generally, the entire controller board is replaced. While it can be expected that the replacement of the controller board will occur frequently in information processing apparatus, it is inconvenient if the problem of inability to decrypt the data stored in the HDD or NVRAM or the like presents itself whenever the controller board is replaced.